1. Related Technical Fields
Related technical fields include data management systems, update file generating systems, and data updating methods.
2. Related Art
Navigation apparatuses that have been commercialized in recent years have a built-in high capacity hard disk serving as a storage medium. These navigation apparatuses are provided with a storage medium that stores map data, display the map data on a monitor in combination with the position of the guided vehicle (e.g., detected by a GPS), and provide route guidance to a destination.
A navigation apparatus that is provided with such a hard disk updates data that is stored on the hard disk by receiving an update file via, for example, low capacity media or a predetermined communication network such as a mobile telephone or the like. The navigation apparatus reads and writes desired data on the hard disk from the update file. Such navigation apparatuses do not require replacing a disk such as a DVD or a CD-ROM to update data.
In addition, in such a navigation apparatus, because multiple data is stored on the storage medium in record units, where a record consists of a plurality of fields, data is updated in the record units without updating all of the data that is stored on the storage medium, by “incremental updating” (see, e.g., Japanese Patent Application Publication No. JP-A-2004-287705).
Specifically, in the incremental updating, a record in which even one byte must be updated is designated as an object of updating. An update file that contains the data for an entire new record is then generated. The navigation apparatus receives the input of this update file and the data that is stored on the storage medium is updated by overwriting the entire record that is stored on the storage medium and is the object of updating by the data for the entire record that is contained in the update file. Thus, because the update file does not contain records that do not need to be updated, the volume of the update file is relatively small, and consequently the amount of communication, the memory volume, and the update time for inputting this update file are reduced.
In addition, navigation apparatuses are known that, in addition to carrying out the route guidance described above, information data related to site information is stored on the storage medium, and search guidance for site information is carried out by displaying the information data on a monitor (see, e.g., Japanese Patent Application Publication No. JP-A-2005-25672, and Japanese Industrial Standards D 0810).